For the purpose of beautifying the asphalt concrete or cement concrete surfaces of floors or walls of buildings, platforms of railroad stations, concourses, pedestrian overpasses and pavements, the practice of forming brick or tile patterns or various other geometrical figures on those surfaces is gaining increasing acceptance these days. Also gaining wide acceptance is forming three-dimensional directional signs directly on walls, floors, etc.
Three most common methods proposed so far for forming three-dimensional patterns or geometrical figures on walls, floors, road surfaces, etc. include:
(a) a method comprising attaching an expanded polyethylene mold to the work surface, applying a projection forming material to fill in the mold, allowing the applied material to harden, and removing the mold by either burning or dissolving it away so as to form a pattern with intended projections and grooves (see Japanese Patent Publication No. 47593/1987); PA1 (b) a method comprising attaching a two-layered mold (having a releasable covering material on its top) to the work surface, applying a projection forming material to fill in the mold, removing the releasable covering material before the projection forming material solidifies or hardens and, after the projection forming material hardens completely, removing the mold to form a pattern with intended projections and grooves [see Japanese Patent Application (KOKAI) No. 233264/1985]; and PA1 (c) a method which is the same as method (b) except that the mold remaining after the releasable covering material is removed is left intact as a joint filler on the work surface [see Japanese Patent Application (KOKAI), No. 111062/1987]. PA1 (A) at least one monomer component selected from among (meth) acrylic acid and esters thereof; PA1 (B) a polymer that can dissolve in said monomer component (A) or that is swollen by said monomer component; and PA1 (C) an aggregate.
The three methods described above have their own defects. In method (a), the appearance of the final pattern is considerably damaged by burning the mold. Even if the mold is dissolved away with the aid of a solvent, solvent staining will occur. In method (c), the mold in the joint can later be damaged or shed from the work surface. In both methods (b) and (c), the releasable covering material has to be removed while the projection forming material remains incompletely hardened, so the unhardened projection forming material deposited on the surface of the covering material can drip in areas where projections are to be formed, which either damages the appearance of the finished pattern or presents difficulty in the pattern forming operation. Further, method (b) requires two removing steps, one for removing the releasable covering material and the other for removing the mold, and this renders the overall operation cumbersome.
A common problem to these conventional methods is that no special tool has been developed for use in removing the mold after the surfacing material hardens and the only tools available today are common screwdrivers with a thin wedge-shaped end and scrapers However, it has not been easy to remove the mold with conventional screwdrivers or scrapers. For instance, in order to remove the mold with a conventional screwdriver, the latter is inserted between the mold and the work surface and the mold is pried to be detached from the work surface. Further, the screwdriver must be kept pushed during the operation but precise removal of the mold is difficult to achieve in this way. Scrapers are suitable for the purpose of removing burrs and other projections from the work surface but not suitable for removing the mold embedded in the surfacing material.